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young may resemble neither parent but revert to an ancestral 

 type, as grand parent, &c., called the laio of reversions, or, 

 from Latin atavus, and ancestor, atavism. 



Analysis of causes which determined the probable quality of 

 the young animal shows seven or more powerful influences in 

 action. 



1st, The young may resemble both parents equally ; 2d, 

 Or one of the parents particularly, aiul the likeness may be in 

 the same sex or the opposite. 3d, The resemblance may 

 revert to grandparents or other ancestors, — atavism. This is 

 recognized by breeders under a variety of names, as "throwing 

 back," "crying back," "• breeding back," &c., and is one of 

 the most influential laws of heredity. It is estimated to occur 

 at the rate of about three cases in ten. 4th, There may be 

 collateral resemblance to uncle, aunt, &c., that is to other issue 

 of the grandparents besides the actual parent of the indi- 

 vidual affected. 5th, The tendency to keep the average of the 

 sexes equal, termed coequal heredity. 6th," The influence of 

 previous impregnation may appear in the resemblance of the 

 young, not to its own sire but to the male that first had fruit- 

 ful intercourse with its dam, or the one by which she last 

 produced offspring. 7th, The influence of temporary condi- 

 tions in either or both parents at the time of conception, 

 called initial heredity. 



To these may be added others, among them the condition 

 and vigor of the dam during the period of pregnancy, and the 

 care and food of the young from birth till it has arrived at an 

 age for profit. 



We need not set ourselves to originate a type, or create, or 

 fix qualities suitable for our purpose. The materials are 

 ready at our hand as the result of others' expenditure and 

 toil, and from these we select. 



Here appears a great obstacle to general progress — there 

 are not enough thoroughbred animals to go around, and how- 

 ever much each one may wish to possess them all our dairy 

 cows cannot be of pure blood. How, then, can the benefit be 



